A new kind of Al-5Ti-0.8C master alloy was fabricated using a self-propagating combustion reaction method and dilution treatment, and the effects of different Al-5Ti-0.8C master alloy contents (0wt%, 0.1wt%, 0.3wt%, 0.5wt%) on the microstructure and elevated temperature mechanical properties of Al-Cu-Mn alloy were investigated. The results show that the Al-5Ti-0.8C master alloy refines the Al-Cu-Mn alloy, increases the amount of θ′(Al₂Cu) precipitates, and reduces their size during heat treatment, resulting in the grain refinement. Moreover, this new master alloy obviously improves the elevated temperature mechanical properties of Al-Cu-Mn alloy, mainly due to the precipitation strengthening caused by the uniform distribution of second phases and fine θ′(Al₂Cu) precipitates, and the formation of Al₃(Ti, Zr) nanoparticles with high thermal stability. Furthermore, the microstructure and mechanical properties of Al-Cu-Mn alloy with 0.3wt% Al-5Ti-0.8C master alloy show the optimal status.